I have heard from some that they are unable to do the cross-eyed 3D thing. I was unable to do the "magic-eye" puzzles from the 90s. I feel your pain. Unless you have some 3D glasses on hand, this is probably the only way I can get these pictures to you online. However, if you do have 3D glasses, I will put some pictures up in a format of your choosing.
The gist of the cross-eyed method is to stare at the two pictures and cross your eyes so a third is formed in the middle of the two. Then relax a little and just look at the middle one. 3D! Here is a link to a more expansive lesson on how to do this.
Click on the pictures of your choice to make bigger:
